Anomalous diurnal patterns of stem xylem water potentials in <i>Larrea tridentata</i>

TitleAnomalous diurnal patterns of stem xylem water potentials in Larrea tridentata
Publication TypeJournal Article
Year of Publication1975
AuthorsSyvertsen JP, Cunningham G.L, Feather T.V
JournalEcology
Volume56
Pagination1423-1428
Date Published1975
Call Number00329
Keywordsarticle, articles, journal, journals, Larrea,photosynthesis, Larrea,stem xylem, Larrea,transpiration, photosynthesis, pressure bomb, soil water, vapor flux, stem xylem, water potentials, transpiration, water potential,Larrea stem xylem
AbstractDiurnal stem xylem H2O potentials of Larrea tridentata (DC.) Cov. were measured with a pressure chamber during the summers of 1973, 1974. Plants growing in dry soils had minimum stem xylem H2O potentials at night and maximum values during the daylight hours. Vertical H2) vapor movements in the soil profile in response to temperature gradients may be implicated although further data are needed to establish their role conclusively. Water vapor apparently moves up our to the rooting zone at night and back down into the rooting zone during the day. The occurrence of this phenomenon probably enhances the ability of Larrea shrubs to maintain photosynthetic activity when soil H2O potentials are low and makes questionable the use of predawn stem xylem H2O potential measurements to assess seasonal trends in plant H2O status.